Updating plugin not working

Hi,
I have to do the update of the plugin “WooCommerce PDF Invoices & Packing Slips” but every time I try to do it, it throw down my site and shows this error: “Briefly unavailable for scheduled maintenance. Try again in a minute.”
Then, after few minutes, it return to work but the plugin isn’t updated.
I have already update my wordpress version at the last one.
So, what I have to do for updating the plugin? why this problem?

Hello Matteo,
““Briefly unavailable for scheduled maintenance. Try again in a minute.” is a message that WordPress shows for any plugin being updated. I don’t know why it doesn’t actually get the latest version for you? Is there enough free space on your server for both the download and the plugin? Due to the PDF tools and included fonts, the plugin is relatively big (compared to other plugins): around 16M on disk and 7M for the download.